Metal-coated paper article and method of making same



Patented June 24, 1930 .UNITED STATES PATENT OFFICE.

ALBERT L, CLAPP, or mnwnns, mAssAcnusE'r'rs METAL-COATED PAPER ARTICLE AND METHOD OF" MAKING SAME No Drawing. Application filed July '16, 1926, Serial No. 123,022. Renewed March 18, 1930.

In my application, Serial No. 94,329, filed March 12, 1926, I have described a paper permeated with a hardening compound having greaseproof, water-resistant and fireproof properties and suitable for manufacture into articles of various shapes.

in accordance with the method disclosed therein, an asbestos-cellulose paper, preferably filled with lime, is formed on a paper machine and is then saturated with a sodium silicate solution. The sodium silicate reacts with the asbestos fiber and lime to produce throughout the paper a gelatinous, gummy material which sets to a hard, rigid com- 15 pound, which imparts the desired characteristics to the paper. While setting, the paper acquires a temper or consistency permitting it to be bent and moulded into articles of various shapes without being cracked or broken, g and in this respect behaves somewhat like ductile sheet metal, such as sheet tin, zinc and the like. Such paper is suitable for manufacture into plates, dishes, baking utensils, and the like, which are rigid d very light.

In certain instances, it ay be desirable to electropla-te such articles with copper, silver, or the like. I have found that if an electroconductingmaterial such as carbon or raphite dust or finely divided metalpow ers or 30 filings is sprinkled onto the surface of the paper after treatment with sodium silicate solution, and the tempered paper 'is then moulded intov an article of the desired shape under pressure at an elevated temperature, a a firm, smooth, electro-conducting surface is produced, on which afirmly adherent metal li'c coating vmay be deposited by the usual electroplatingmethods.

A procedure which may be practised in 40 producing metallic-coated paper articles such as herein desired, may be substantially as follows. Sixtyparts of cellulose fiber, e. g.,

kraft or sulphite fiber, and forty partsof as bestos fiber are laced in the beater engine,

together with cient water to ensure circulation of the mass. The fibers are thoroughly mixed by ,operation of the engine, during which time about 10% to, 15% lime, based on the dry weight of fiber, is introduced and uniiormly disseminated throughout the fibers.

The furnish is then run ofi on a cylinder or F ourdrinier machine, and the paper web is dried. The dry web is then saturated with a solution of sodium silicate, as by passage through a bath composed of equal parts by weight of a solution of sodium silicate Baum) and water. Any excess solution may be extracted from the web by passage through squeeze rolls. The sodium silicate acts upon the asbestos to destroy the fibrous character- 00 istics thereof, resulting in a gummy plastic which behaves in some respects like Portland cement as itbecomes set. Finely divided carbon, graphite, or other conducting material is sprinkled or dusted onto both surfaces of the paper immediately after the silicate treatment.

Immediately after treatment with sodium silicate, the paper is more or less weak and flabby, but upon reducing its water content to about 20% to 30%, it acquires a temper or condition suitable for moulding. Blanks for articles of the desired shapeare cut from a sheet and are'moulded under a pressure of about 500 pounds per square inch, and at a temperature of about 1"60 to 180 F. Preferably a temperature of 200 F. is not exceeded in'moulding, owing to the fact that blistering is liable to take place. A setting or hardening of the article takes place immediately under the given conditions. The moulded article has a smooth, firm, elect'ro-conducting surface and is removable from the mould without encountering any difficulty from sticking. q

The moulded article may now be electro plated with the desired metal, such as copper, as from a solution of copper sulphate, by the usual electroplating methods, and followed,

if desired, by silverplating. Owing to the water-resistant property of the rigidified paper, there is no tendency for the article to undergo disintegration in the plating bath. The metal deposits on the smooth,-electroconducting surface as a smooth,,firm, adher- 9 ing coating, which may be burnished or similarly treated.

Such articles as plates, platters, dishes,

cooking utensils, and the like, may be made from paper of about 10 to 15 points in-thickness, are rigid, very light, and possess an appearance resembling solid metallic articles. The furnish from which the paper is made may vary in composition. For example, the lime may be substituted by other filling materials, such as Portland cement or magnesium carbonate, or may be entirely omitted, but with less favorable results. The proportions of asbestos and cellulose fiber may vary, and, in fact, if the proportion of lime or its equivalent is raised to about 20%, the asbestos fiber may be omitted. This latter expedient, however, leads to inferior results, and in general it has been found preferable to use approximately equal parts of the two fibers.

Having thus described certain embodiments of this invention, it should be obvious that these are susceptible of various changes and modifications without departing from the spirit or scope of invention as set forth in the appended claims.

What I claim is:

1. A method which comprises forming paper comprising a material capable of reacting with a reagent to produce a hardening compound, treating the paper with the reagent, applying electro-conductive material to the surface of the paper, moulding the paper under pressure at an elevated temperature into an article of the desired shape, and then electro-depositing a metal on the article.

2. A method which comprises forming paper comprising a material capable of reacting with sodium silicate solution to produce a hardening compound, treating the paper with a sodium silicate solution, applying electro-conductive material to the surface of the 1' paper, forming the paper into an article of the desired shape, and then electro-depositing a metal on the article.

3. A method which comprises forming paper comprising a material capable of reacting with sodium silicate solution to produce a hardening compound, treating the paper with a sodium silicate solution, applying electro-conductive material to the surface of the paper, moulding the paper under pressure at an elevated temperature into an article.

of the desired shape, and then electro-depositing a metal on the article.

4. A'method which comprises treating an asbestos-cellulose paper with a solution of sodium silicate, applying finely divided conducting material to the surface of the paper, moulding the paper under pressure at an elevated temperature into an article of the desired shape, and then electro-depositing a.

metal on the article.

5'. A method which comprises treating an asbestos-cellulose paper filled with lime with a sodium silicate solution, applying finely divided electro-conductive material to the surface of the treated paper, moulding the paper under pressure at an elevated temperature a sodium silicate solution, applying finely divided electro-conductive material to the surface of the treated paper, reducing the water content of the treated paper to about 20% to 30%, moulding the paper under pressure at an elevated temperature into an article of the desired shape, and shaped article.

7. A method which comprises treating an asbestos-cellulose paper filled with lime with a sodium silicate solution, applying finely divided electro-conductive .material to the surface of the treated paper, reducing the water content of the treated paper to about 20% to 30%, moulding the paper under a pressure of about 500 pounds at a temperature of 160 to' 180 F.', into an article of the desired shape, and then electro-depositing a metal on the shaped article. In testimony whereof, I have aflixed m signature.

ALBERT L. GLAPP.

then electroplating the 

